Toyota and Lexus models for 2008 had a much greater incidence of sudden, unintended acceleration than other brands, according to Consumer Reports’ analysis of a National Highway Traffic Safety Administration (NHTSA) safety complaints database. In our review of 2008 model-year data, Ford also stood out with a significant number of related complaints. Both automakers had a disproportionate number of occurrences for their market share, though the statistical likelihood of experiencing such events is low.

In analyzing all 5,916 reports on 2008 models, Consumer Reports’ Auto Test Center and Statistics Department identified 166 cases in which the complaint described sustained unintended acceleration that the driver found difficult or impossible to control. Such incidents prompted a related safety advisory focused on floor-mat entrapment issued by both NHTSA and Toyota in September, 2009.

We used 2008 models to provide a snapshot across all automakers and identify possible issues. The scope was further narrowed to complaints submitted before Aug. 28, 2009, when a California family was killed in a Lexus sedan experiencing uncontrollable acceleration, to eliminate the impact media coverage had in drawing more submissions.

Toyota, Lexus lead with complaintsThe sudden-acceleration incidents were distributed over 22 brands, but they were not spread evenly. Forty-seven complaints were about Toyota models and five were for Lexus vehicles. Between them, Toyota and Lexus accounted for more than a third of all the unintended-acceleration incidents we found among 2008-model vehicles. Seen another way, Toyota racked up more unintended-acceleration complaints than Chrysler, GM, Honda, and Nissan combined.

As major automakers, Toyota Motor Corporation and Ford Motor Company sell more vehicles than most competitors. To put the figures into proper perspective, we compared the number of complaints against overall market share.

Automaker

2008 model-year complaints*

Share of complaints

2007/2008 average market share

Toyota

52

41%

16%

Ford

36

28%

16%

Chrysler

11

9%

12%

General Motors

7

5%

23%

Honda

5

4%

10%

Nissan

4

3%

6%

*Reflects complaints submitted prior to August 28th, 2009.

Looking at all complaints on 2008 models through November, we find that Toyota had a significant increase after the media attention following the California tragedy and the company’s safety advisory mailings to owners. In November, the total count for Toyota and Lexus rises to 80 incidents, representing 48 percent of the complaints from all brands.

In the acceleration cases we scrutinized, drivers reported that sometimes their car lurched from a standstill, fighting the brakes. Other times it took off while cruising the highway, or while parking, or even while going in reverse.Representative Toyota owner comments pulled from the NHTSA database:

“While entering an on-ramp the [2008 Tacoma] truck accelerated on its own, going out of control crashing sideways into a guard rail…”

“My 2008 Prius accelerated almost out of control. I was merging onto an expressway when the accelerator seemed to have a life of its own and took off at an incredibly high rate of speed…”

“I felt the vehicle [2008 Lexus ES 350] increasing in speed to about 90 mph, without depressing the accelerator. I had been on cruise control at about 73 mph… [A] passenger screamed at me to slow down. I was unable to do so, even after stepping forcefully on the brakes.”

Ford complaints are also high, GM especially lowWith 36 complaints, Ford was the only other manufacturer with a disproportionately high number of reported cases. Some consumers’ personal accounts indicate that the pedal arrangement in the popular F-150 pickup makes it too easy to hit the brake and accelerator at the same time, although there are other detailed sudden-acceleration events that are not readily explained.

Representative 2008 Ford F-150 complaints from the NHTSA database:

“This Ford F-150 pickup truck has the widest gas (accelerator) pedal I have ever seen and as a result my right foot continues to press down on it, even after I have started applying the brake pedal with the same foot.”

“I entered the vehicle, started the engine, and put the vehicle in drive. The engine immediately increased in rpm to the point where the rear tires began spinning on the gravel. I put the transmission in Neutral and the engine rpm increased. I removed my foot from the brake and the engine continued at a very high rpm. I then depressed and released the accelerator and the engine returned to a normal idle.”

“...the truck spontaneously accelerated at full throttle with my foot firmly on the brake… I was advancing without applying the accelerator. With the brakes fully applied, I continued to advance into the parking lot and I immediately shifted into Park in attempt to stop the vehicle. The vehicle came to a stop and the engine was racing at full throttle in Park.”

The bottom lineBecause it is dependent upon motorist submissions, the NHTSA complaint database does not reflect all sudden, unintended acceleration cases. But the data does show statistically more complaints for certain Toyota, Lexus, and Ford brand models.

Another way of looking at the extent of complaints is to compare them to model-year sales. Based on our analysis, the ratio of reports for experiencing such a problem on 2008 model-year vehicle from Toyota Motor Corporation is about one in nearly 50,000. The Ford Motor Company’s reported risk is about one in nearly 65,000. In contrast, the reported risk for a GM model is just one in 500,000.

Toyota has announced several steps it is taking to mitigate the risks of floor-mat entrapment and provide “smart throttle” technology (allowing the brake pedal to override the accelerator), but our analysis indicates other problems likely exist.

We hope to see the introduction of smart-throttle technology on all vehicles, providing a means for the driver to quickly and safely regain control of the car in unintended acceleration scenarios.